A hard disk drive generally includes a stack of rotating disks or platters, a spindle motor which causes the disks to rotate, read/write heads which fly above the surface of the disks, an actuator motor (known as a "voice coil motor" or VCM) which controls the positioning of the read/write heads, power circuitry to provide electrical power to the spindle and voice coil motors, and control circuitry to control the operation of the spindle and voice coil motors.
For any particular type of computer, such as the line of computers incorporating Intel 80X86 microprocessors, a variety of compatible disk drives are typically offered. These disk drives may vary in the amount of memory available, the number of disks or platters in the stack, and the rate at which data can be written to or read from the disks. The power and control circuitry required to drive the spindle and voice coil motors for the disk drive generally varies with the parameters of the disk drive.
In the past, manufacturers of hard disk drive electronics have designed the motor power and control circuitry as four separate integrated circuit (IC) chips: a voice coil motor power chip, a voice coil motor control chip, a spindle motor power chip, and a spindle motor control chip. Each of these chips might vary from one disk drive type to another. Thus, one disk drive type might require four IC chips which are all different from those of another disk drive type.
Another prior art device integrated the actuator motor power and control circuits on one integrated circuit, and the spindle motor power and control circuits on another integrated circuit. Since the power portion of each chip would vary with the type of actuator and spindle motors used, different chips would be required to drive different motors.
Because integrated circuit chips are expensive to design and manufacture, it would be desirable to reduce the total number of chips used to provide disk drive motor power and control. Moreover, it would be advantageous if one or more of the chips providing power and control to the disk drive motors could be used in several different types of disk drives.